1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
# Grammar
```
program := line ( '\n' line )*
line := label | instruction | directive
label := identifier ':'
directive := '.globl' identifier | '.section' identifier | '.ascii' string
instruction := identifier operands*
operands := operand ( ',' operand )*
operand := identifier | immediate
identifier := alpha alnum+
immediate := integer
string := '"' ( char | escape )* '"'
char := any character except '"' and '\'
escape := '\' ( '"' | '\' )
integer := digit+
alpha := lower | upper | '_'
alnum := alpha | digit
lower := 'a' | 'b' | ... | 'z'
upper := 'A' | 'B' | ... | 'Z'
digit := '0' | '1' | ... | '9'
```